1
|
Milano L, Gautam A, Caldecott KW. DNA damage and transcription stress. Mol Cell 2024; 84:70-79. [PMID: 38103560 DOI: 10.1016/j.molcel.2023.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Genome damage and transcription are intimately linked. Tens to hundreds of thousands of DNA lesions arise in each cell each day, many of which can directly or indirectly impede transcription. Conversely, the process of gene expression is itself a source of endogenous DNA lesions as a result of the susceptibility of single-stranded DNA to damage, conflicts with the DNA replication machinery, and engagement by cells of topoisomerases and base excision repair enzymes to regulate the initiation and progression of gene transcription. Although such processes are tightly regulated and normally accurate, on occasion, they can become abortive and leave behind DNA breaks that can drive genome rearrangements, instability, or cell death.
Collapse
Affiliation(s)
- Larissa Milano
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Amit Gautam
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Keith W Caldecott
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| |
Collapse
|
2
|
Sarni D, Barroso S, Shtrikman A, Irony-Tur Sinai M, Oren YS, Aguilera A, Kerem B. Topoisomerase 1-dependent R-loop deficiency drives accelerated replication and genomic instability. Cell Rep 2022; 40:111397. [PMID: 36170822 PMCID: PMC9532845 DOI: 10.1016/j.celrep.2022.111397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 06/26/2022] [Accepted: 08/31/2022] [Indexed: 11/29/2022] Open
Abstract
DNA replication is a complex process tightly regulated to ensure faithful genome duplication, and its perturbation leads to DNA damage and genomic instability. Replication stress is commonly associated with slow and stalled replication forks. Recently, accelerated replication has emerged as a non-canonical form of replication stress. However, the molecular basis underlying fork acceleration is largely unknown. Here, we show that mutated HRAS activation leads to increased topoisomerase 1 (TOP1) expression, causing aberrant replication fork acceleration and DNA damage by decreasing RNA-DNA hybrids or R-loops. In these cells, restoration of TOP1 expression or mild replication inhibition rescues the perturbed replication and reduces DNA damage. Furthermore, TOP1 or RNaseH1 overexpression induces accelerated replication and DNA damage, highlighting the importance of TOP1 equilibrium in regulating R-loop homeostasis to ensure faithful DNA replication and genome integrity. Altogether, our results dissect a mechanism of oncogene-induced DNA damage by aberrant replication fork acceleration. Increased TOP1 expression by mutated RAS reduces R loops Low R-loop levels promote accelerated replication and DNA damage TOP1 restoration or mild replication inhibition rescue DNA acceleration and damage High TOP1 expression is associated with replication mutagenesis in cancer
Collapse
Affiliation(s)
- Dan Sarni
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem 91904, Israel
| | - Sonia Barroso
- Department of Genome Biology, Andalusian Center of Molecular Biology and Regenerative Medicine CABIMER, Seville Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Alon Shtrikman
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem 91904, Israel
| | - Michal Irony-Tur Sinai
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem 91904, Israel
| | - Yifat S Oren
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem 91904, Israel
| | - Andrés Aguilera
- Department of Genome Biology, Andalusian Center of Molecular Biology and Regenerative Medicine CABIMER, Seville Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem 91904, Israel.
| |
Collapse
|
3
|
Lin WL, Chen JK, Wen X, He W, Zarceno GA, Chen Y, Chen S, Paull TT, Liu HW. DDX18 prevents R-loop-induced DNA damage and genome instability via PARP-1. Cell Rep 2022; 40:111089. [PMID: 35858569 DOI: 10.1016/j.celrep.2022.111089] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 04/02/2022] [Accepted: 06/22/2022] [Indexed: 01/05/2023] Open
Abstract
R loops occur frequently in genomes and contribute to fundamental biological processes at multiple levels. Consequently, understanding the molecular and cellular biology of R loops has become an emerging area of research. Here, it is shown that poly(ADP-ribose) polymerase-1 (PARP-1) can mediate the association of DDX18, a putative RNA helicase, with R loops thereby modulating R-loop homeostasis in endogenous R-loop-prone and DNA lesion regions. DDX18 depletion results in aberrant endogenous R-loop accumulation, which leads to DNA-replication defects. In addition, DDX18 depletion renders cells more sensitive to DNA-damaging agents and reduces RPA32 and RAD51 foci formation in response to irradiation. Notably, DDX18 depletion leads to γH2AX accumulation and genome instability, and RNase H1 overexpression rescues all the DNA-repair defects caused by DDX18 depletion. Taken together, these studies uncover a function of DDX18 in R-loop-mediated events and suggest a role for PARP-1 in mediating the binding of specific DDX-family proteins with R loops in cells.
Collapse
Affiliation(s)
- Wen-Ling Lin
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jung-Kuei Chen
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Xuemei Wen
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Wei He
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA; School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Geovanny A Zarceno
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Yutian Chen
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Shi Chen
- School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Shenzhen Institute of Translational Medicine, Health Science Center, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518055, China
| | - Tanya T Paull
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Hung-Wen Liu
- Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas at Austin, Austin, TX 78712, USA; Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA.
| |
Collapse
|
4
|
Silva S, Guillén-Mendoza C, Aguilera A. RNase H1 Hybrid-Binding Domain-Based Tools for Cellular Biology Studies of DNA-RNA Hybrids in Mammalian Cells. Methods Mol Biol 2022; 2528:115-125. [PMID: 35704188 DOI: 10.1007/978-1-0716-2477-7_8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
R loops are abundant noncanonical DNA-RNA hybrid structures that can occur during DNA-based processes, such as transcription, replication and DNA damage, and can lead both to physiologically favorable and pathological outcomes. With an increasing body of work feeding the field of R loop biology, our understanding of the processes in which R loops intervene and the consequences of meddling with R loop formation and dissolution has greatly increased but it has also led to new questions and sometimes opposing possibilities. Proper detection of these structures is a crucial factor to advance our knowledge about R loops and factors associated with their formation and removal. Here, we describe the use of fluorescently tagged HBD, the hybrid-binding domain of RNase H1, as a tool for analyzing DNA-RNA hybrids in different contexts using live-cell microscopy and immunofluorescence experiments.
Collapse
Affiliation(s)
- Sónia Silva
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Cristina Guillén-Mendoza
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain.
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain.
| |
Collapse
|
5
|
Zhao H, Hartono SR, de Vera KMF, Yu Z, Satchi K, Zhao T, Sciammas R, Sanz L, Chédin F, Barlow J. Senataxin and RNase H2 act redundantly to suppress genome instability during class switch recombination. eLife 2022; 11:78917. [PMID: 36542058 PMCID: PMC9771370 DOI: 10.7554/elife.78917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 11/17/2022] [Indexed: 12/24/2022] Open
Abstract
Class switch recombination generates distinct antibody isotypes critical to a robust adaptive immune system, and defects are associated with autoimmune disorders and lymphomagenesis. Transcription is required during class switch recombination to recruit the cytidine deaminase AID-an essential step for the formation of DNA double-strand breaks-and strongly induces the formation of R loops within the immunoglobulin heavy-chain locus. However, the impact of R loops on double-strand break formation and repair during class switch recombination remains unclear. Here, we report that cells lacking two enzymes involved in R loop removal-senataxin and RNase H2-exhibit increased R loop formation and genome instability at the immunoglobulin heavy-chain locus without impacting its transcriptional activity, AID recruitment, or class switch recombination efficiency. Senataxin and RNase H2-deficient cells also exhibit increased insertion mutations at switch junctions, a hallmark of alternative end joining. Importantly, these phenotypes were not observed in cells lacking senataxin or RNase H2B alone. We propose that senataxin acts redundantly with RNase H2 to mediate timely R loop removal, promoting efficient repair while suppressing AID-dependent genome instability and insertional mutagenesis.
Collapse
Affiliation(s)
- Hongchang Zhao
- Department of Microbiology and Molecular Genetics, University of California, DavisDavisUnited States
| | - Stella R Hartono
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | | | - Zheyuan Yu
- Department of Microbiology and Molecular Genetics, University of California, DavisDavisUnited States,Graduate Group in Biostatistics, University of California, DavisDavisUnited States
| | - Krishni Satchi
- Department of Microbiology and Molecular Genetics, University of California, DavisDavisUnited States
| | - Tracy Zhao
- Department of Microbiology and Molecular Genetics, University of California, DavisDavisUnited States
| | - Roger Sciammas
- Center for Immunology and Infectious Diseases, University of California, DavisDavisUnited States
| | - Lionel Sanz
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Jacqueline Barlow
- Department of Microbiology and Molecular Genetics, University of California, DavisDavisUnited States
| |
Collapse
|
6
|
Leela JK, Raghunathan N, Gowrishankar J. Topoisomerase I Essentiality, DnaA-Independent Chromosomal Replication, and Transcription-Replication Conflict in Escherichia coli. J Bacteriol 2021; 203:e0019521. [PMID: 34124945 DOI: 10.1128/JB.00195-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Topoisomerase I (Topo I) of Escherichia coli, encoded by topA, acts to relax negative supercoils in DNA. Topo I deficiency results in hypernegative supercoiling, formation of transcription-associated RNA-DNA hybrids (R-loops), and DnaA- and oriC-independent constitutive stable DNA replication (cSDR), but some uncertainty persists as to whether topA is essential for viability in E. coli and related enterobacteria. Here, we show that several topA alleles, including ΔtopA, confer lethality in derivatives of wild-type E. coli strain MG1655. Viability in the absence of Topo I was restored with two perturbations, neither of which reversed the hypernegative supercoiling phenotype: (i) in a reduced-genome strain (MDS42) or (ii) by an RNA polymerase (RNAP) mutation, rpoB*35, that has been reported to alleviate the deleterious consequences of RNAP backtracking and transcription-replication conflicts. Four phenotypes related to cSDR were identified for topA mutants: (i) one of the topA alleles rescued ΔdnaA lethality; (ii) in dnaA+ derivatives, Topo I deficiency generated a characteristic copy number peak in the terminus region of the chromosome; (iii) topA was synthetically lethal with rnhA (encoding RNase HI, whose deficiency also confers cSDR); and (iv) topA rnhA synthetic lethality was itself rescued by ΔdnaA. We propose that the terminal lethal consequence of hypernegative DNA supercoiling in E. coli topA mutants is RNAP backtracking during transcription elongation and associated R-loop formation, which in turn leads to transcription-replication conflicts and to cSDR. IMPORTANCE In all life forms, double-helical DNA exists in a topologically supercoiled state. The enzymes DNA gyrase and topoisomerase I act, respectively, to introduce and to relax negative DNA supercoils in Escherichia coli. That gyrase deficiency leads to bacterial death is well established, but the essentiality of topoisomerase I for viability has been less certain. This study confirms that topoisomerase I is essential for E. coli viability and suggests that in its absence, aberrant chromosomal DNA replication and excessive transcription-replication conflicts occur that are responsible for lethality.
Collapse
|
7
|
Klotz-Noack K, Klinger B, Rivera M, Bublitz N, Uhlitz F, Riemer P, Lüthen M, Sell T, Kasack K, Gastl B, Ispasanie SSS, Simon T, Janssen N, Schwab M, Zuber J, Horst D, Blüthgen N, Schäfer R, Morkel M, Sers C. SFPQ Depletion Is Synthetically Lethal with BRAF V600E in Colorectal Cancer Cells. Cell Rep 2021; 32:108184. [PMID: 32966782 DOI: 10.1016/j.celrep.2020.108184] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 04/28/2020] [Accepted: 09/02/2020] [Indexed: 12/21/2022] Open
Abstract
Oncoproteins such as the BRAFV600E kinase endow cancer cells with malignant properties, but they also create unique vulnerabilities. Targeting of BRAFV600E-driven cytoplasmic signaling networks has proved ineffective, as patients regularly relapse with reactivation of the targeted pathways. We identify the nuclear protein SFPQ to be synthetically lethal with BRAFV600E in a loss-of-function shRNA screen. SFPQ depletion decreases proliferation and specifically induces S-phase arrest and apoptosis in BRAFV600E-driven colorectal and melanoma cells. Mechanistically, SFPQ loss in BRAF-mutant cancer cells triggers the Chk1-dependent replication checkpoint, results in decreased numbers and reduced activities of replication factories, and increases collision between replication and transcription. We find that BRAFV600E-mutant cancer cells and organoids are sensitive to combinations of Chk1 inhibitors and chemically induced replication stress, pointing toward future therapeutic approaches exploiting nuclear vulnerabilities induced by BRAFV600E.
Collapse
Affiliation(s)
- Kathleen Klotz-Noack
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Bertram Klinger
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; IRI Life Sciences & Institute of Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Maria Rivera
- EPO Experimentelle Pharmakologie und Onkologie Berlin-Buch GmbH, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Natalie Bublitz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Florian Uhlitz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; IRI Life Sciences & Institute of Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Pamela Riemer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany
| | - Mareen Lüthen
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Thomas Sell
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; IRI Life Sciences & Institute of Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Katharina Kasack
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Bastian Gastl
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany
| | - Sylvia S S Ispasanie
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany
| | - Tincy Simon
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany
| | - Nicole Janssen
- Dr. Margarete Fischer-Bosch - Institute of Clinical Pharmacology, Auerbachstraße 112, 70376 Stuttgart, Germany; University of Tuebingen, 72074 Tuebingen, Germany
| | - Matthias Schwab
- Dr. Margarete Fischer-Bosch - Institute of Clinical Pharmacology, Auerbachstraße 112, 70376 Stuttgart, Germany; Departments of Clinical Pharmacology, Pharmacy and Biochemistry, University of Tuebingen, Auf der Morgenstelle 8, 72074 Tuebingen, Germany; German Cancer Consortium (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Johannes Zuber
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria; Medical University of Vienna, VBC, 1030 Vienna, Austria
| | - David Horst
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Nils Blüthgen
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; IRI Life Sciences & Institute of Theoretical Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Reinhold Schäfer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany; Charité Comprehensive Cancer Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany
| | - Markus Morkel
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Christine Sers
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health. Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, 10117 Berlin, Germany; German Cancer Consortium (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| |
Collapse
|
8
|
Fagan-Solis KD, Simpson DA, Kumar RJ, Martelotto LG, Mose LE, Rashid NU, Ho AY, Powell SN, Wen YH, Parker JS, Reis-Filho JS, Petrini JHJ, Gupta GP. A P53-Independent DNA Damage Response Suppresses Oncogenic Proliferation and Genome Instability. Cell Rep 2020; 30:1385-1399.e7. [PMID: 32023457 DOI: 10.1016/j.celrep.2020.01.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/30/2019] [Accepted: 01/03/2020] [Indexed: 12/20/2022] Open
Abstract
The Mre11-Rad50-Nbs1 complex is a DNA double-strand break sensor that mediates a tumor-suppressive DNA damage response (DDR) in cells undergoing oncogenic stress, yet the mechanisms underlying this effect are poorly understood. Using a genetically inducible primary mammary epithelial cell model, we demonstrate that Mre11 suppresses proliferation and DNA damage induced by diverse oncogenic drivers through a p53-independent mechanism. Breast tumorigenesis models engineered to express a hypomorphic Mre11 allele exhibit increased levels of oncogene-induced DNA damage, R-loop accumulation, and chromosomal instability with a characteristic copy number loss phenotype. Mre11 complex dysfunction is identified in a subset of human triple-negative breast cancers and is associated with increased sensitivity to DNA-damaging therapy and inhibitors of ataxia telangiectasia and Rad3 related (ATR) and poly (ADP-ribose) polymerase (PARP). Thus, deficiencies in the Mre11-dependent DDR drive proliferation and genome instability patterns in p53-deficient breast cancers and represent an opportunity for therapeutic exploitation.
Collapse
|
9
|
Kalev P, Hyer ML, Gross S, Konteatis Z, Chen CC, Fletcher M, Lein M, Aguado-Fraile E, Frank V, Barnett A, Mandley E, Goldford J, Chen Y, Sellers K, Hayes S, Lizotte K, Quang P, Tuncay Y, Clasquin M, Peters R, Weier J, Simone E, Murtie J, Liu W, Nagaraja R, Dang L, Sui Z, Biller SA, Travins J, Marks KM, Marjon K. MAT2A Inhibition Blocks the Growth of MTAP-Deleted Cancer Cells by Reducing PRMT5-Dependent mRNA Splicing and Inducing DNA Damage. Cancer Cell 2021; 39:209-224.e11. [PMID: 33450196 DOI: 10.1016/j.ccell.2020.12.010] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 10/30/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022]
Abstract
The methylthioadenosine phosphorylase (MTAP) gene is located adjacent to the cyclin-dependent kinase inhibitor 2A (CDKN2A) tumor-suppressor gene and is co-deleted with CDKN2A in approximately 15% of all cancers. This co-deletion leads to aggressive tumors with poor prognosis that lack effective, molecularly targeted therapies. The metabolic enzyme methionine adenosyltransferase 2α (MAT2A) was identified as a synthetic lethal target in MTAP-deleted cancers. We report the characterization of potent MAT2A inhibitors that substantially reduce levels of S-adenosylmethionine (SAM) and demonstrate antiproliferative activity in MTAP-deleted cancer cells and tumors. Using RNA sequencing and proteomics, we demonstrate that MAT2A inhibition is mechanistically linked to reduced protein arginine methyltransferase 5 (PRMT5) activity and splicing perturbations. We further show that DNA damage and mitotic defects ensue upon MAT2A inhibition in HCT116 MTAP-/- cells, providing a rationale for combining the MAT2A clinical candidate AG-270 with antimitotic taxanes.
Collapse
Affiliation(s)
- Peter Kalev
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Marc L Hyer
- Pharmacology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Stefan Gross
- Biochemistry and Biophysics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Zenon Konteatis
- Chemistry, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Chi-Chao Chen
- Bioinformatics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Mark Fletcher
- Bioinformatics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Max Lein
- Drug Metabolism and Pharmacokinetics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Elia Aguado-Fraile
- Clinical Biomarkers, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Victoria Frank
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Amelia Barnett
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Everton Mandley
- Pharmacology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Joshua Goldford
- Cell Metabolism, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Yue Chen
- Drug Metabolism and Pharmacokinetics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Katie Sellers
- Cell Metabolism, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Sebastian Hayes
- Cell Metabolism, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Kate Lizotte
- Cell Metabolism, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Phong Quang
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Yesim Tuncay
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Michelle Clasquin
- Cell Metabolism, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Rachel Peters
- Toxicology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Jaclyn Weier
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Eric Simone
- Chemistry, Manufacturing and Control, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Joshua Murtie
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA; Pharmacology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Wei Liu
- Bioinformatics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Raj Nagaraja
- Drug Metabolism and Pharmacokinetics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Lenny Dang
- Biochemistry and Biophysics, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Zhihua Sui
- Chemistry, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Scott A Biller
- Chemistry, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Jeremy Travins
- Chemistry, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Kevin M Marks
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA
| | - Katya Marjon
- Biology, Agios Pharmaceuticals, Inc., Cambridge, MA 02139, USA.
| |
Collapse
|
10
|
Abstract
This Outlook discusses the findings by Pérez-Calero et al. reporting that, in addition to its RNA processing role, UAP56/DDX39B is a key helicase required to eliminate harmful cotranscriptional RNA structures that otherwise would block transcription and replication. R loops arise from hybridization of RNA transcripts with template DNA during transcription. Unrepaired R loops lead to transcription–replication collisions, causing DNA damage and genomic instability. In this issue of Genes & Development, Pérez-Calero and colleagues (pp. 898–912) identify UAP56 as a cotranscriptional RNA–DNA helicase that unwinds R loops. They found that UAP56 helicase activity is required to remove R loops formed from different sources and prevent R-loop accumulation genome-wide at actively transcribed genes.
Collapse
Affiliation(s)
- Jacob P Matson
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA
| |
Collapse
|
11
|
Pérez-Calero C, Bayona-Feliu A, Xue X, Barroso SI, Muñoz S, González-Basallote VM, Sung P, Aguilera A. UAP56/DDX39B is a major cotranscriptional RNA-DNA helicase that unwinds harmful R loops genome-wide. Genes Dev 2020; 34:898-912. [PMID: 32439635 PMCID: PMC7328515 DOI: 10.1101/gad.336024.119] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/20/2020] [Indexed: 01/10/2023]
Abstract
In this study, Pérez-Calero et al. set out to investigate the role of UAP56/DDX39B in R-loop removal. Using in vitro and in vivo approaches, the authors demonstrate that UAP56 functions as a DNA–RNA helicase required to eliminate harmful cotranscriptional RNA structures that otherwise would block transcription and replication. Nonscheduled R loops represent a major source of DNA damage and replication stress. Cells have different ways to prevent R-loop accumulation. One mechanism relies on the conserved THO complex in association with cotranscriptional RNA processing factors including the RNA-dependent ATPase UAP56/DDX39B and histone modifiers such as the SIN3 deacetylase in humans. We investigated the function of UAP56/DDX39B in R-loop removal. We show that UAP56 depletion causes R-loop accumulation, R-loop-mediated genome instability, and replication fork stalling. We demonstrate an RNA–DNA helicase activity in UAP56 and show that its overexpression suppresses R loops and genome instability induced by depleting five different unrelated factors. UAP56/DDX39B localizes to active chromatin and prevents the accumulation of RNA–DNA hybrids over the entire genome. We propose that, in addition to its RNA processing role, UAP56/DDX39B is a key helicase required to eliminate harmful cotranscriptional RNA structures that otherwise would block transcription and replication.
Collapse
Affiliation(s)
- Carmen Pérez-Calero
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Aleix Bayona-Feliu
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Xiaoyu Xue
- Molecular Biophysics and Biochemistry, School of Medicine, University of Yale, New Haven, Connecticut 06510, USA.,Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas 78666, USA
| | - Sonia I Barroso
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Sergio Muñoz
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Víctor M González-Basallote
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| | - Patrick Sung
- Molecular Biophysics and Biochemistry, School of Medicine, University of Yale, New Haven, Connecticut 06510, USA.,Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER) Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Sevilla 41092, Spain
| |
Collapse
|
12
|
Gottifredi V, Wiesmüller L. Current Understanding of RAD52 Functions: Fundamental and Therapeutic Insights. Cancers (Basel) 2020; 12:E705. [PMID: 32192055 DOI: 10.3390/cancers12030705] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 02/07/2023] Open
Abstract
In this Special Issue, we would like to focus on the various functions of the RAD52 helicase-like protein and the current implications of such findings for cancer treatment. Over the last few years, various laboratories have discovered particular activities of mammalian RAD52—both in S and M phase—that are distinct from the auxiliary role of yeast RAD52 in homologous recombination. At DNA double-strand breaks, RAD52 was demonstrated to spur alternative pathways to compensate for the loss of homologous recombination functions. At collapsed replication forks, RAD52 activates break-induced replication. In the M phase, RAD52 promotes the finalization of DNA replication. Its compensatory role in the resolution of DNA double-strand breaks has put RAD52 in the focus of synthetic lethal strategies, which is particularly relevant for cancer treatment.
Collapse
|
13
|
Skourti-Stathaki K, Torlai Triglia E, Warburton M, Voigt P, Bird A, Pombo A. R-Loops Enhance Polycomb Repression at a Subset of Developmental Regulator Genes. Mol Cell 2019; 73:930-945.e4. [PMID: 30709709 PMCID: PMC6414425 DOI: 10.1016/j.molcel.2018.12.016] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 09/14/2018] [Accepted: 12/14/2018] [Indexed: 12/26/2022]
Abstract
R-loops are three-stranded nucleic acid structures that form during transcription, especially over unmethylated CpG-rich promoters of active genes. In mouse embryonic stem cells (mESCs), CpG-rich developmental regulator genes are repressed by the Polycomb complexes PRC1 and PRC2. Here, we show that R-loops form at a subset of Polycomb target genes, and we investigate their contribution to Polycomb repression. At R-loop-positive genes, R-loop removal leads to decreased PRC1 and PRC2 recruitment and Pol II activation into a productive elongation state, accompanied by gene derepression at nascent and processed transcript levels. Stable removal of PRC2 derepresses R-loop-negative genes, as expected, but does not affect R-loops, PRC1 recruitment, or transcriptional repression of R-loop-positive genes. Our results highlight that Polycomb repression does not occur via one mechanism but consists of different layers of repression, some of which are gene specific. We uncover that one such mechanism is mediated by an interplay between R-loops and RING1B recruitment. R-loops form at a subset of PcG target genes R-loops contribute to PcG recruitment genome-wide Loss of R-loops leads to transcriptional activation of R-loop-positive PcG targets R-loops and PRC1 contribute to transcriptional repression of PcG targets
Collapse
Affiliation(s)
- Konstantina Skourti-Stathaki
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK; Berlin Institute for Medical Systems Biology, Max Delbrueck Centre for Molecular Medicine, Berlin-Buch 13092, Germany.
| | - Elena Torlai Triglia
- Berlin Institute for Medical Systems Biology, Max Delbrueck Centre for Molecular Medicine, Berlin-Buch 13092, Germany
| | - Marie Warburton
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
| | - Philipp Voigt
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, EH9 3BF Edinburgh, UK
| | - Ana Pombo
- Berlin Institute for Medical Systems Biology, Max Delbrueck Centre for Molecular Medicine, Berlin-Buch 13092, Germany; Berlin Institute of Health, Berlin, Germany; Institute for Biology, Humboldt-Universitat zu Berlin, Berlin, Germany.
| |
Collapse
|
14
|
Silva S, Camino LP, Aguilera A. Human mitochondrial degradosome prevents harmful mitochondrial R loops and mitochondrial genome instability. Proc Natl Acad Sci U S A 2018; 115:11024-9. [PMID: 30301808 DOI: 10.1073/pnas.1807258115] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
R loops are nucleic acid structures comprising an DNA-RNA hybrid and a displaced single-stranded DNA. These structures may occur transiently during transcription, playing essential biological functions. However, persistent R loops may become pathological as they are important drivers of genome instability and have been associated with human diseases. The mitochondrial degradosome is a functionally conserved complex from bacteria to human mitochondria. It is composed of the ATP-dependent RNA and DNA helicase SUV3 and the PNPase ribonuclease, playing a central role in mitochondrial RNA surveillance and degradation. Here we describe a new role for the mitochondrial degradosome in preventing the accumulation of pathological R loops in the mitochondrial DNA, in addition to preventing dsRNA accumulation. Our data indicate that, similar to the molecular mechanisms acting in the nucleus, RNA surveillance mechanisms in the mitochondria are crucial to maintain its genome integrity by counteracting pathological R-loop accumulation.
Collapse
|
15
|
Tummala H, Dokal AD, Walne A, Ellison A, Cardoso S, Amirthasigamanipillai S, Kirwan M, Browne I, Sidhu JK, Rajeeve V, Rio-Machin A, Seraihi AA, Duncombe AS, Jenner M, Smith OP, Enright H, Norton A, Aksu T, Özbek NY, Pontikos N, Cutillas P, Dokal I, Vulliamy T. Genome instability is a consequence of transcription deficiency in patients with bone marrow failure harboring biallelic ERCC6L2 variants. Proc Natl Acad Sci U S A 2018; 115:7777-82. [PMID: 29987015 DOI: 10.1073/pnas.1803275115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bone marrow failure (BMF) is an inherited life-threatening condition characterized by defective hematopoiesis, developmental abnormalities, and predisposition to cancer. BMF caused by ERCC6L2 mutations is considered to be a genome instability syndrome, because DNA repair is compromised in patient cells. In this study, we report BMF cases with biallelic disease-causing variants and provide evidence from patients’ cells that transcription deficiency can explain the genome instability. Specifically, we demonstrate that ERCC6L2 participates in RNA polymerase II-mediated transcription via interaction with DNA-dependent protein kinase (DNA-PK) and resolves DNA–RNA hybrids (R loops). Collectively, our data point to a causal mechanism in BMF in which patients with ERCC6L2 mutations are defective in the repair of transcription-associated DNA damage. Biallelic variants in the ERCC excision repair 6 like 2 gene (ERCC6L2) are known to cause bone marrow failure (BMF) due to defects in DNA repair and mitochondrial function. Here, we report on eight cases of BMF from five families harboring biallelic variants in ERCC6L2, two of whom present with myelodysplasia. We confirm that ERCC6L2 patients’ lymphoblastoid cell lines (LCLs) are hypersensitive to DNA-damaging agents that specifically activate the transcription coupled nucleotide excision repair (TCNER) pathway. Interestingly, patients’ LCLs are also hypersensitive to transcription inhibitors that interfere with RNA polymerase II (RNA Pol II) and display an abnormal delay in transcription recovery. Using affinity-based mass spectrometry we found that ERCC6L2 interacts with DNA-dependent protein kinase (DNA-PK), a regulatory component of the RNA Pol II transcription complex. Chromatin immunoprecipitation PCR studies revealed ERCC6L2 occupancy on gene bodies along with RNA Pol II and DNA-PK. Patients’ LCLs fail to terminate transcript elongation accurately upon DNA damage and display a significant increase in nuclear DNA–RNA hybrids (R loops). Collectively, we conclude that ERCC6L2 is involved in regulating RNA Pol II-mediated transcription via its interaction with DNA-PK to resolve R loops and minimize transcription-associated genome instability. The inherited BMF syndrome caused by biallelic variants in ERCC6L2 can be considered as a primary transcription deficiency rather than a DNA repair defect.
Collapse
|
16
|
Komseli ES, Pateras IS, Krejsgaard T, Stawiski K, Rizou SV, Polyzos A, Roumelioti FM, Chiourea M, Mourkioti I, Paparouna E, Zampetidis CP, Gumeni S, Trougakos IP, Pefani DE, O’Neill E, Gagos S, Eliopoulos AG, Fendler W, Chowdhury D, Bartek J, Gorgoulis VG. A prototypical non-malignant epithelial model to study genome dynamics and concurrently monitor micro-RNAs and proteins in situ during oncogene-induced senescence. BMC Genomics 2018; 19:37. [PMID: 29321003 PMCID: PMC5763532 DOI: 10.1186/s12864-017-4375-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/11/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Senescence is a fundamental biological process implicated in various pathologies, including cancer. Regarding carcinogenesis, senescence signifies, at least in its initial phases, an anti-tumor response that needs to be circumvented for cancer to progress. Micro-RNAs, a subclass of regulatory, non-coding RNAs, participate in senescence regulation. At the subcellular level micro-RNAs, similar to proteins, have been shown to traffic between organelles influencing cellular behavior. The differential function of micro-RNAs relative to their subcellular localization and their role in senescence biology raises concurrent in situ analysis of coding and non-coding gene products in senescent cells as a necessity. However, technical challenges have rendered in situ co-detection unfeasible until now. METHODS In the present report we describe a methodology that bypasses these technical limitations achieving for the first time simultaneous detection of both a micro-RNA and a protein in the biological context of cellular senescence, utilizing the new commercially available SenTraGorTM compound. The method was applied in a prototypical human non-malignant epithelial model of oncogene-induced senescence that we generated for the purposes of the study. For the characterization of this novel system, we applied a wide range of cellular and molecular techniques, as well as high-throughput analysis of the transcriptome and micro-RNAs. RESULTS This experimental setting has three advantages that are presented and discussed: i) it covers a "gap" in the molecular carcinogenesis field, as almost all corresponding in vitro models are fibroblast-based, even though the majority of neoplasms have epithelial origin, ii) it recapitulates the precancerous and cancerous phases of epithelial tumorigenesis within a short time frame under the light of natural selection and iii) it uses as an oncogenic signal, the replication licensing factor CDC6, implicated in both DNA replication and transcription when over-expressed, a characteristic that can be exploited to monitor RNA dynamics. CONCLUSIONS Consequently, we demonstrate that our model is optimal for studying the molecular basis of epithelial carcinogenesis shedding light on the tumor-initiating events. The latter may reveal novel molecular targets with clinical benefit. Besides, since this method can be incorporated in a wide range of low, medium or high-throughput image-based approaches, we expect it to be broadly applicable.
Collapse
Affiliation(s)
- Eirini-Stavroula Komseli
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Ioannis S. Pateras
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Thorbjørn Krejsgaard
- Department of Immunology and Microbiology, University of Copenhagen, Blegdamsvej 3c, DK-2200 Copenhagen, Denmark
| | - Konrad Stawiski
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, 15 Mazowiecka St. 92-215, Lodz, Poland
| | - Sophia V. Rizou
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Alexander Polyzos
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Fani-Marlen Roumelioti
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Maria Chiourea
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Ioanna Mourkioti
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Eleni Paparouna
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Christos P. Zampetidis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
| | - Sentiljana Gumeni
- Department of Cell Biology and Biophysics, Faculty of Biology, National & Kapodistrian University of Athens, GR-15784 Athens, Greece
| | - Ioannis P. Trougakos
- Department of Cell Biology and Biophysics, Faculty of Biology, National & Kapodistrian University of Athens, GR-15784 Athens, Greece
| | - Dafni-Eleftheria Pefani
- CRUK/MRC Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ UK
| | - Eric O’Neill
- CRUK/MRC Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ UK
| | - Sarantis Gagos
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
| | - Aristides G. Eliopoulos
- Department of Biology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research & Technology-Hellas, GR-70013 Heraklion, Crete Greece
| | - Wojciech Fendler
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, 15 Mazowiecka St. 92-215, Lodz, Poland
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA 02215 USA
| | - Dipanjan Chowdhury
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Ave, Boston, MA 02215 USA
- Harvard Medical School, 25 Shattuck St, Boston, MA 02115 USA
| | - Jiri Bartek
- Genome Integrity Unit, Danish Cancer Society Research Centre, Strandboulevarden 49, DK-2100 Copenhagen, Denmark
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Hněvotínská, 1333/5, 779 00 Olomouc, Czech Republic
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, SE-171 77 Stockholm, Sweden
| | - Vassilis G. Gorgoulis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, National & Kapodistrian University of Athens, 75 Mikras Asias St, GR-11527 Athens, Greece
- Biomedical Research Foundation of the Academy of Athens, 4 Soranou Ephessiou St, GR-11527 Athens, Greece
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Wilmslow Road, Manchester, M20 4QL UK
| |
Collapse
|
17
|
Wiedemann EM, Peycheva M, Pavri R. DNA Replication Origins in Immunoglobulin Switch Regions Regulate Class Switch Recombination in an R-Loop-Dependent Manner. Cell Rep 2016; 17:2927-42. [PMID: 27974207 DOI: 10.1016/j.celrep.2016.11.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 09/07/2016] [Accepted: 11/11/2016] [Indexed: 11/22/2022] Open
Abstract
Class switch recombination (CSR) at the immunoglobulin heavy chain (IgH) locus generates antibody isotypes. CSR depends on double-strand breaks (DSBs) induced by activation-induced cytidine deaminase (AID). Although DSB formation and repair machineries are active in G1 phase, efficient CSR is dependent on cell proliferation and S phase entry; however, the underlying mechanisms are obscure. Here, we show that efficient CSR requires the replicative helicase, the Mcm complex. Mcm proteins are enriched at IgH switch regions during CSR, leading to assembly of facultative replication origins that require Mcm helicase function for productive CSR. Assembly of CSR-associated origins is facilitated by R loops and promotes the physical proximity (synapsis) of recombining switch regions, which is reduced by R loop inhibition or Mcm complex depletion. Thus, R loops contribute to replication origin specification that promotes DSB resolution in CSR. This suggests a mechanism for the dependence of CSR on S phase and cell division.
Collapse
|
18
|
Abstract
In this issue of Molecular Cell, Taneja et al. (2017) uncover a dual role for the conserved chromatin remodeler Fft3 in the maintenance of silent heterochromatin and the suppression of replication barriers at euchromatic loci through controlled histone turnover.
Collapse
Affiliation(s)
- Anna Fortuny
- Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR 7216 CNRS/Université Paris Diderot, 35 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Sophie E Polo
- Laboratory of Epigenome Integrity, Epigenetics & Cell Fate Centre, UMR 7216 CNRS/Université Paris Diderot, 35 rue Hélène Brion, 75205 Paris Cedex 13, France.
| |
Collapse
|
19
|
García-Pichardo D, Cañas JC, García-Rubio ML, Gómez-González B, Rondón AG, Aguilera A. Histone Mutants Separate R Loop Formation from Genome Instability Induction. Mol Cell 2017; 66:597-609.e5. [PMID: 28575656 DOI: 10.1016/j.molcel.2017.05.014] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/03/2017] [Accepted: 05/15/2017] [Indexed: 01/02/2023]
Abstract
R loops have positive physiological roles, but they can also be deleterious by causing genome instability, and the mechanisms for this are unknown. Here we identified yeast histone H3 and H4 mutations that facilitate R loops but do not cause instability. R loops containing single-stranded DNA (ssDNA), versus RNA-DNA hybrids alone, were demonstrated using ssDNA-specific human AID and bisulfite. Notably, they are similar size regardless of whether or not they induce genome instability. Contrary to mutants causing R loop-mediated instability, these histone mutants do not accumulate H3 serine-10 phosphate (H3S10-P). We propose a two-step mechanism in which, first, an altered chromatin facilitates R loops, and second, chromatin is modified, including H3S10-P, as a requisite for compromising genome integrity. Consistently, these histone mutations suppress the high H3S10 phosphorylation and genomic instability of hpr1 and sen1 mutants. Therefore, contrary to what was previously believed, R loops do not cause genome instability by themselves.
Collapse
Affiliation(s)
- Desiré García-Pichardo
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville 41092, Spain
| | - Juan C Cañas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville 41092, Spain
| | - María L García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville 41092, Spain
| | - Belén Gómez-González
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville 41092, Spain
| | - Ana G Rondón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville 41092, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville 41092, Spain.
| |
Collapse
|
20
|
Song C, Hotz-Wagenblatt A, Voit R, Grummt I. SIRT7 and the DEAD-box helicase DDX21 cooperate to resolve genomic R loops and safeguard genome stability. Genes Dev 2017; 31:1370-1381. [PMID: 28790157 PMCID: PMC5580657 DOI: 10.1101/gad.300624.117] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/13/2017] [Indexed: 01/09/2023]
Abstract
Here, Song et al. show that the DEAD-box RNA helicase DDX21 efficiently unwinds RNA/DNA hybrids (R loops) in vivo and in vitro and prevents DNA damage. Their findings reveal a novel mechanism by which accumulation of R loops by DDX21 depletion leads to genomic instability. R loops are three-stranded nucleic acid structures consisting of an RNA:DNA heteroduplex and a “looped-out” nontemplate strand. As aberrant formation and persistence of R loops block transcription elongation and cause DNA damage, mechanisms that resolve R loops are essential for genome stability. Here we show that the DEAD (Asp–Glu–Ala–Asp)-box RNA helicase DDX21 efficiently unwinds R loops and that depletion of DDX21 leads to accumulation of cellular R loops and DNA damage. Significantly, the activity of DDX21 is regulated by acetylation. Acetylation by CBP inhibits DDX21 activity, while deacetylation by SIRT7 augments helicase activity and overcomes R-loop-mediated stalling of RNA polymerases. Knockdown of SIRT7 leads to the same phenotype as depletion of DDX21 (i.e., increased formation of R loops and DNA double-strand breaks), indicating that SIRT7 and DDX21 cooperate to prevent R-loop accumulation, thus safeguarding genome integrity. Moreover, DDX21 resolves estrogen-induced R loops on estrogen-responsive genes in breast cancer cells, which prevents the blocking of transcription elongation on these genes.
Collapse
Affiliation(s)
- Chenlin Song
- Molecular Biology of the Cell II, German Cancer Research Center (DKFZ), DKFZ-Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) Alliance, D-69120 Heidelberg, Germany
| | - Agnes Hotz-Wagenblatt
- Bioinformatics Group, Core Facility Genomics and Proteomics, German Cancer Research Center (DKFZ), DKFZ-Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) Alliance, D-69120 Heidelberg, Germany
| | - Renate Voit
- Molecular Biology of the Cell II, German Cancer Research Center (DKFZ), DKFZ-Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) Alliance, D-69120 Heidelberg, Germany
| | - Ingrid Grummt
- Molecular Biology of the Cell II, German Cancer Research Center (DKFZ), DKFZ-Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH) Alliance, D-69120 Heidelberg, Germany
| |
Collapse
|
21
|
Catania F. From intronization to intron loss: How the interplay between mRNA-associated processes can shape the architecture and the expression of eukaryotic genes. Int J Biochem Cell Biol 2017; 91:136-144. [PMID: 28673893 DOI: 10.1016/j.biocel.2017.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/25/2017] [Accepted: 06/30/2017] [Indexed: 12/29/2022]
Abstract
Transcription-coupled processes such as capping, splicing, and cleavage/polyadenylation participate in the journey from genes to proteins. Although they are traditionally thought to serve only as steps in the generation of mature mRNAs, a synthesis of available data indicates that these processes could also act as a driving force for the evolution of eukaryotic genes. A theoretical framework for how mRNA-associated processes may shape gene structure and expression has recently been proposed. Factors that promote splicing and cleavage/polyadenylation in this framework compete for access to overlapping or neighboring signals throughout the transcription cycle. These antagonistic interactions allow mechanisms for intron gain and splice site recognition as well as common trends in eukaryotic gene structure and expression to be coherently integrated. Here, I extend this framework further. Observations that largely (but not exclusively) revolve around the formation of DNA-RNA hybrid structures, called R loops, and promoter directionality are integrated. Additionally, the interplay between splicing factors and cleavage/polyadenylation factors is theorized to also affect the formation of intragenic DNA double-stranded breaks thereby contributing to intron loss. The most notable prediction in this proposition is that RNA molecules can mediate intron loss by serving as a template to repair DNA double-stranded breaks. The framework presented here leverages a vast body of empirical observations, logically extending previous suggestions, and generating verifiable predictions to further substantiate the view that the intracellular environment plays an active role in shaping the structure and the expression of eukaryotic genes.
Collapse
Affiliation(s)
- Francesco Catania
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany.
| |
Collapse
|
22
|
Abstract
For nearly three decades, R loops have been closely linked with class switch recombination (CSR), the process that generates antibody isotypes and that occurs via a complex cascade initiated by transcription-coupled mutagenesis in switch recombination sequences. R loops form during transcription of switch recombination sequences in vitro and in vivo, and there is solid evidence that R loops are required for efficient class switching. The classical model of R loops posits that they boost mutation rates by generating stable and long tracts of single-stranded DNA that serve as the substrate for activation induced deaminase (AID), the enzyme that initiates the CSR reaction cascade by co-transcriptionally mutating ssDNA in switch recombination sequences. Though logical and compelling, this model has not been supported by in vivo evidence. Indeed, several reports suggest that R loops may not be involved in recruiting AID activity to switch regions, meaning that R loops probably serve other unanticipated roles in CSR. Here, I review the key findings in this field to date and propose hypotheses that could help towards elucidating the precise function of R loops in CSR.
Collapse
Affiliation(s)
- Rushad Pavri
- Research Institute of Molecular Pathology (IMP), Campus Vienna Biocenter-1, Vienna Biocenter, Vienna 1030, Austria.
| |
Collapse
|
23
|
Wahba L, Costantino L, Tan FJ, Zimmer A, Koshland D. S1-DRIP-seq identifies high expression and polyA tracts as major contributors to R-loop formation. Genes Dev 2017; 30:1327-38. [PMID: 27298336 PMCID: PMC4911931 DOI: 10.1101/gad.280834.116] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/11/2016] [Indexed: 12/16/2022]
Abstract
In this study, Wahba et al. investigate how and where DNA–RNA hybrids, which form when an RNA molecule hybridizes to the complementary genomic locus, appear throughout the genome. They present a novel whole-genome method, S1-DRIP-seq, for mapping hybrid-prone regions in S. cerevisiae and identify the first global genomic features that play a causal role in R-loop formation in yeast. R loops form when transcripts hybridize to homologous DNA on chromosomes, yielding a DNA:RNA hybrid and a displaced DNA single strand. R loops impact the genome of many organisms, regulating chromosome stability, gene expression, and DNA repair. Understanding the parameters dictating R-loop formation in vivo has been hampered by the limited quantitative and spatial resolution of current genomic strategies for mapping R loops. We report a novel whole-genome method, S1-DRIP-seq (S1 nuclease DNA:RNA immunoprecipitation with deep sequencing), for mapping hybrid-prone regions in budding yeast Saccharomyces cerevisiae. Using this methodology, we identified ∼800 hybrid-prone regions covering 8% of the genome. Given the pervasive transcription of the yeast genome, this result suggests that R-loop formation is dictated by characteristics of the DNA, RNA, and/or chromatin. We successfully identified two features highly predictive of hybrid formation: high transcription and long homopolymeric dA:dT tracts. These accounted for >60% of the hybrid regions found in the genome. We demonstrated that these two factors play a causal role in hybrid formation by genetic manipulation. Thus, the hybrid map generated by S1-DRIP-seq led to the identification of the first global genomic features causal for R-loop formation in yeast.
Collapse
Affiliation(s)
- Lamia Wahba
- Department of Cell and Molecular Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Lorenzo Costantino
- Department of Cell and Molecular Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Frederick J Tan
- Department of Embryology, Carnegie Institution for Science, Baltimore, Maryland 21218, USA
| | - Anjali Zimmer
- Department of Cell and Molecular Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Douglas Koshland
- Department of Cell and Molecular Biology, University of California at Berkeley, Berkeley, California 94720, USA
| |
Collapse
|
24
|
Abstract
Aberrant R-loop structures are increasingly being realized as an important contributor to human disease. R loops, which are mainly co-transcriptional, abundant RNA/DNA hybrids, form naturally and can indeed be beneficial for transcription regulation at certain loci. However, their unwanted persistence elsewhere or in particular situations can lead to DNA double-strand breaks, chromosome rearrangements, and hypermutation, which are all sources of genomic instability. Mutations in genes involved in R-loop resolution or mutations leading to R-loop formation at specific genes affect the normal physiology of the cell. We discuss here the examples of diseases for which a link with R loops has been described, as well as how disease-causing mutations might participate in the development and/or progression of diseases that include repeat-associated conditions, other neurological disorders, and cancers.
Collapse
Affiliation(s)
- Patricia Richard
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| |
Collapse
|
25
|
Abstract
The fragile X-related disorders are members of the Repeat Expansion Diseases, a group of genetic conditions resulting from an expansion in the size of a tandem repeat tract at a specific genetic locus. The repeat responsible for disease pathology in the fragile X-related disorders is CGG/CCG and the repeat tract is located in the 5′ UTR of the FMR1 gene, whose protein product FMRP, is important for the proper translation of dendritic mRNAs in response to synaptic activation. There are two different pathological FMR1 allele classes that are distinguished only by the number of repeats. Premutation alleles have 55–200 repeats and confer risk of fragile X-associated tremor/ataxia syndrome and fragile X-associated primary ovarian insufficiency. Full mutation alleles on the other hand have >200 repeats and result in fragile X syndrome, a disorder that affects learning and behavior. Different symptoms are seen in carriers of premutation and full mutation alleles because the repeat number has paradoxical effects on gene expression: Epigenetic changes increase transcription from premutation alleles and decrease transcription from full mutation alleles. This review will cover what is currently known about the mechanisms responsible for these changes in FMR1 expression and how they may relate to other Repeat Expansion Diseases that also show repeat-mediated changes in gene expression.
Collapse
Affiliation(s)
- Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health , Bethesda, MD, USA
| | - Daman Kumari
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health , Bethesda, MD, USA
| |
Collapse
|
26
|
Abstract
R loops are three-stranded nucleic acid structures that comprise nascent RNA hybridized with the DNA template, leaving the nontemplate DNA single-stranded. These structures form naturally during transcription even though their persistent formation can have deleterious effects on genome integrity. Interestingly, an increasing number of studies also suggest that R loops function as potential gene expression regulators. Here, Skourti-Stathaki and Proudfoot review the most recent findings about R loops, highlighting their opposite roles in cellular fitness. R loops are three-stranded nucleic acid structures that comprise nascent RNA hybridized with the DNA template, leaving the nontemplate DNA single-stranded. R loops form naturally during transcription even though their persistent formation can be a risky outcome with deleterious effects on genome integrity. On the other hand, over the last few years, an increasingly strong case has been built for R loops as potential regulators of gene expression. Therefore, understanding their function and regulation under these opposite situations is essential to fully characterize the mechanisms that control genome integrity and gene expression. Here we review recent findings about these interesting structures that highlight their opposite roles in cellular fitness.
Collapse
Affiliation(s)
| | - Nicholas J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| |
Collapse
|
27
|
Santos-Pereira JM, Herrero AB, Moreno S, Aguilera A. Npl3, a new link between RNA-binding proteins and the maintenance of genome integrity. Cell Cycle 2014; 13:1524-9. [PMID: 24694687 DOI: 10.4161/cc.28708] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The mRNA is co-transcriptionally bound by a number of RNA-binding proteins (RBPs) that contribute to its processing and formation of an export-competent messenger ribonucleoprotein particle (mRNP). In the last few years, increasing evidence suggests that RBPs play a key role in preventing transcription-associated genome instability. Part of this instability is mediated by the accumulation of co-transcriptional R loops, which may impair replication fork (RF) progression due to collisions between transcription and replication machineries. In addition, some RBPs have been implicated in DNA repair and/or the DNA damage response (DDR). Recently, the Npl3 protein, one of the most abundant heterogeneous nuclear ribonucleoproteins (hnRNPs) in yeast, has been shown to prevent transcription-associated genome instability and accumulation of RF obstacles, partially associated with R-loop formation. Interestingly, Npl3 seems to have additional functions in DNA repair, and npl3∆ mutants are highly sensitive to genotoxic agents, such as the antitumor drug trabectedin. Here we discuss the role of Npl3 in particular, and RBPs in general, in the connection of transcription with replication and genome instability, and its effect on the DDR.
Collapse
Affiliation(s)
- José M Santos-Pereira
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER; Universidad de Sevilla-CSIC; Seville, Spain
| | - Ana B Herrero
- Instituto de Biología Molecular y Celular del Cáncer; Universidad de Salamanca-CSIC; Salamanca, Spain
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica; Universidad de Salamanca-CSIC; Salamanca, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER; Universidad de Sevilla-CSIC; Seville, Spain
| |
Collapse
|
28
|
Herrera-Moyano E, Mergui X, García-Rubio ML, Barroso S, Aguilera A. The yeast and human FACT chromatin-reorganizing complexes solve R-loop-mediated transcription-replication conflicts. Genes Dev 2014; 28:735-48. [PMID: 24636987 DOI: 10.1101/gad.234070.113] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The chromatin-reorganizing complex FACT functions in transcription elongation and DNA replication, yet its role in replication is not well understood. Here, Herrera-Moyano et al. find increased recombination rates and genetic instability in yeast mutants and FACT-depleted human cells. The results demonstrate a conserved function for FACT in the resolution of transcription–replication conflicts mediated by R loops. This study therefore links the roles of FACT in transcription elongation and DNA replication. FACT (facilitates chromatin transcription) is a chromatin-reorganizing complex that swaps nucleosomes around the RNA polymerase during transcription elongation and has a role in replication that is not fully understood yet. Here we show that recombination factors are required for the survival of yeast FACT mutants, consistent with an accumulation of DNA breaks that we detected by Rad52 foci and transcription-dependent hyperrecombination. Breaks also accumulate in FACT-depleted human cells, as shown by γH2AX foci and single-cell electrophoresis. Furthermore, FACT-deficient yeast and human cells show replication impairment, which in yeast we demonstrate by ChIP–chip (chromatin immunoprecipitation [ChIP] coupled with microarray analysis) of Rrm3 to occur genome-wide but preferentially at highly transcribed regions. Strikingly, in yeast FACT mutants, high levels of Rad52 foci are suppressed by RNH1 overexpression; R loops accumulate at high levels, and replication becomes normal when global RNA synthesis is inhibited in FACT-depleted human cells. The results demonstrate a key function of FACT in the resolution of R-loop-mediated transcription–replication conflicts, likely associated with a specific chromatin organization.
Collapse
|
29
|
Santos-Pereira JM, Herrero AB, García-Rubio ML, Marín A, Moreno S, Aguilera A. The Npl3 hnRNP prevents R-loop-mediated transcription-replication conflicts and genome instability. Genes Dev 2013; 27:2445-58. [PMID: 24240235 PMCID: PMC3841734 DOI: 10.1101/gad.229880.113] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 10/11/2013] [Indexed: 12/18/2022]
Abstract
Transcription is a major obstacle for replication fork (RF) progression and a cause of genome instability. Part of this instability is mediated by cotranscriptional R loops, which are believed to increase by suboptimal assembly of the nascent messenger ribonucleoprotein particle (mRNP). However, no clear evidence exists that heterogeneous nuclear RNPs (hnRNPs), the basic mRNP components, prevent R-loop stabilization. Here we show that yeast Npl3, the most abundant RNA-binding hnRNP, prevents R-loop-mediated genome instability. npl3Δ cells show transcription-dependent and R-loop-dependent hyperrecombination and genome-wide replication obstacles as determined by accumulation of the Rrm3 helicase. Such obstacles preferentially occur at long and highly expressed genes, to which Npl3 is preferentially bound in wild-type cells, and are reduced by RNase H1 overexpression. The resulting replication stress confers hypersensitivity to double-strand break-inducing agents. Therefore, our work demonstrates that mRNP factors are critical for genome integrity and opens the option of using them as therapeutic targets in anti-cancer treatment.
Collapse
Affiliation(s)
- José M. Santos-Pereira
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain
| | - Ana B. Herrero
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, 37008 Salamanca, Spain
| | - María L. García-Rubio
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Antonio Marín
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| | - Sergio Moreno
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-Universidad de Salamanca, 37008 Salamanca, Spain
- Instituto de Biología Funcional y Genómica, CSIC-Universidad de Salamanca, 37007 Salamanca, Spain
| | - Andrés Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-Consejo Superior de Investigaciones Científicas (CSIC), 41092 Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
| |
Collapse
|
30
|
Abstract
A protein long recognized for its role in DNA repair has now paradoxically been implicated in DNA damage.
Collapse
Affiliation(s)
- Sue Mei Tan-Wong
- is at the Sir William Dunn School of Pathology , University of Oxford , Oxford , United Kingdom
| | | |
Collapse
|
31
|
Wahba L, Gore SK, Koshland D. The homologous recombination machinery modulates the formation of RNA-DNA hybrids and associated chromosome instability. eLife 2013; 2:e00505. [PMID: 23795288 PMCID: PMC3679537 DOI: 10.7554/elife.00505] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 05/02/2013] [Indexed: 12/24/2022] Open
Abstract
Genome instability in yeast and mammals is caused by RNA–DNA hybrids that form as a result of defects in different aspects of RNA biogenesis. We report that in yeast mutants defective for transcription repression and RNA degradation, hybrid formation requires Rad51p and Rad52p. These proteins normally promote DNA–DNA strand exchange in homologous recombination. We suggest they also directly promote the DNA–RNA strand exchange necessary for hybrid formation since we observed accumulation of Rad51p at a model hybrid-forming locus. Furthermore, we provide evidence that Rad51p mediates hybridization of transcripts to homologous chromosomal loci distinct from their site of synthesis. This hybrid formation in trans amplifies the genome-destabilizing potential of RNA and broadens the exclusive co-transcriptional models that pervade the field. The deleterious hybrid-forming activity of Rad51p is counteracted by Srs2p, a known Rad51p antagonist. Thus Srs2p serves as a novel anti-hybrid mechanism in vivo. DOI:http://dx.doi.org/10.7554/eLife.00505.001 Cells with an unusually large number of mutations—either in the form of changes to the DNA sequence or changes in the number or structure of chromosomes—are said to show genome instability. Although these mutations sometimes boost an organism's chances of survival and reproduction, they more often have detrimental effects, which can include cancer. Genome instability can arise as a result of mistakes occurring during the repair of damaged DNA, or due to inappropriate hybridization of RNA to its DNA template. These RNA–DNA hybrids had been thought to occur strictly during the transcription of DNA into RNA. During this process, the two strands of the DNA molecule separate behind the moving RNA polymerase, and this provides an opportunity for the newly formed RNA to hybridize back to its DNA template. When these RNA–DNA hybrids persist, they give rise to DNA damage that leads to genome instability. Although much is known about the factors that prevent the formation of hybrids, or promote their removal, little is known about how hybrids form in the first place. Now, Wahba et al. have identified one such mechanism in the model yeast, Saccharomyces cerevisiae. It involves a protein called Rad51p, which helps to join stretches of nucleic acids together to repair breaks in DNA. However, Wahba et al. showed that if Rad51p is not properly regulated, it can also trigger the formation of RNA–DNA hybrids; yeast cells that lack the gene for Rad51p showed significantly reduced levels of hybrid formation. Moreover, dysfunctional Rad51p causes RNA sequences to anneal to DNA throughout the genome, rather than just at the site in which the RNA was originally produced. This means that RNA sequences produced during transcription are much more of a threat to genomic stability than previously thought. The work of Wahba et al. presents a paradox in which a protein that is normally involved in repairing DNA can itself cause damage if it is not carefully regulated. It also raises the possibility that the elevated levels of Rad51p expression observed in cancer cells could be a cause, rather than a consequence, of mutations. DOI:http://dx.doi.org/10.7554/eLife.00505.002
Collapse
Affiliation(s)
- Lamia Wahba
- Department of Cell and Molecular Biology , Howard Hughes Medical Institute, University of California, Berkeley , Berkeley , United States ; Department of Biology , Johns Hopkins University , Baltimore , United States
| | | | | |
Collapse
|